Electric switch



Jn 3R W@ m. P. M. Mums RAQQ* ELECTRIC SWITCH Filed Jan. 25, 1948 Patented Jan. 3l, i950 abiti ELECTRIC SWITCH Reinhard P. H. Hinds, C hislehurst, England Application .llanuary 23, 1948, Serial No.`3,880 lin Great Britain October 28, 1946 Section 1, Public Law 690, August 8, 1946 Patent expires October 28, 1966 This invention relates to electric switches of the push-pull type. In such switches as usually constructed, the sliding operating bolt itself forms or carries a bridging contact which engages a pair of stationary spring contacts. In the switches of the present invention, the sliding bolt is formed with a cam profile which operates to displace laterally a separate bridging contact. With this arrangement the electrical contact making portion of the switch may be completely insulated from the operating bolt and the danger of a short circuit thereby greatly reduced.

In the preferred form, the switch of the present invention comprises an insulating body formed with a bore, a recess disposed to one side of the bore and a channel connecting the recess to the bore, an operating bolt having portions of different cross section longitudinally slidable within the bore, a pair of contact members extending into the recess, a bridging contact disposed within the recess on the side of the contact members remote from the bore spring means urging the bridging contact into lengagement with the contact members and a pin displaceable within the channel in the body by longitudinal movement of the operating bolt for moving the bridging contact out of engagement with the contact members against the action of the spring.

Other features and advantages of the invention will suiliciently appear from the following description of the particular switch embodying the invention, which is shown in the accompanying drawing. In thisV drawing, Figure l is a longitudinal section through the switch,'whileFigure 2 is a transverse section on the line 2--2 of Figure 1.

The switch illustrated comprises an insulating body 3 of substantially cylindrical shape formed near one end with a diametrical bore, one end of which is of enlarged diameter and oi D-shape. A metal guide tube 4 extends through the bore in the body, an external D-shaped flange at one end of the tube engaging in the enlarged portion of the bore. The other end of the tube projects from the body and is externally screw-threaded for adapting it to serve as a mounting stem for the device. A lock nut 5 engaged on this portion Vof the tube secures the latter to the body and other such nuts 6 and I aliow the tube and thus the switch body to be secured to a mounting panel. A metal operating bolt E iits slidably within the bore of the guide tube, one end of the bolt projecting from the threaded end of the guide tube and carrying an operating knob 9 of insulating material. The other end of the bolt is reduced in diameter and riveted over a washer, which thus forms a head preventing the bolt from being withdrawn from the guide tube.

The operating bolt is formed with two axially spaced profile portions in the form of circumferential grooves or` recesses of arcuate cross section, one of which is of greater depth than the other. The permitted travel of the operating bolt within the guide tube isV such that the centre line of either groovecan be brought on to the axis 'of the body. At the end remote from the operating Yboltand its guide tube, the body is formed `with a cylindrical chamber I4. From this chamber. a radial channel'extends to the bore containing the guide tube, and registers with a side wall opening in the form of an'aperture in the guide tube. An operating structure including a steel ball I0, tting freely in the axial bore, can thus engage in either of the grooves in the operating bolt and be moved axially of the body by longitudinal movement of the bolt. y

Two other channels in the body, disposed on opposite sides of the axis, `extend from the chamber I4 to thelower face of the body. The lower parts of these channels are of reduced diameter and their enlarged upper part contain cylindrical electrode or contact members I I, whose upper ends project into the chamber and whose lower ends are made hollow to receive conductors passed through the lower ends of the bores. Grub screws secure the cables within the contactmemgers and hold the latter in position within the Ody.

' A bridging contact in the form of a metal ldisc I2 is movably disposed within the chamber i4 and is urged into engagement with the Contact members by spring means in the form of a coil compression spring i3. The electrode or switch terminal members I I are complemental with the member I 2 in forming separable and closable switch contact means. The bridging contact disc has a central hole, into which iits the reduced upper end of a pin I5 of insulating material slidably disposed in the axial channel of the body and cooperable with the ball lll to form said operating structure. The recessed lower end of pin I5 engages the steel ball Ill, which in turn engages the operating bolt S. The dimensions of the parts are such that when the deeper of the two grooves in the operating bolt lies opposite the axial channel in the body (as shown in the drawing) it allows the spring i3 t0 move the bridging disc I2 into engagement with the contact members II, while when the shallower groove is brought opposite the axial channel, the

bridging contact is moved by ball l0 and pin l5 against the action of spring I3 and is held out of engagement with one or both of the contacts The cylindrical body 3 is formed in two parts, whichlare secured together by the guide tube 4 and nut 5. The chamber |ll,-the axial channel in which the pin l5 works and the channels which receive the contact member Il are constituted by mating recesses formed in the meeting faces of the two body parts.

I claim:

1. An `electric switch of the push pull type comprising an insulating body formed with a bore, a chamber spaced radially from said bore and disposed to one side thereof and a radial channel communicating between the chamber and the bore, a tubular mounting stem disposed in said -bore and having an attaching portion projecting axially outwardly thereof, said stem -f having a side-wall opening registering with said channel, an electrode member embedded in said body and extending from a position in said chamber to a position accessible exteriorly of the body, a contact member in said chamber and movable therein axially of said channel between positions respectively contacting and sepa.- rated from said electrode', spring means in the chamber urging the contact member axially of said chamber toward said bore, an operating bolt slidable axially in the tubular mounting member, an operating structure disposed in said channel and side-wall opening between the switch contact :member and said bolt and movable axially in said channel, and said Vbolt having axially spaced recesses of different depth selectively registerable with said operating structure, the deeper of said recesses .accommodating movenient'fof the switch element axially of the channel-into one of said positions and cooperating with said spring and saidstructure for yieldably resisting axial displacement of the bolt, the other of said recesses beingof -a depth maintaining said operating structure axially outwardly of the channel against the force of the spring for maintaining the switch element in the other of its positions and cooperating with the spring and said structure for yieldably resisting axial displacement of the bolt.

2. An electric switch of the push pull type comprising an insulating body formed with a bore,

`a chamber spaced radially from said bore and disposed to one side thereof and a radial channel communicating between the chamber and the bore, a guide tube disposed in said bore, said guide tube having a side-wall opening registering with said channel, separable and closable switch contact means disposed in said chamber, an operating structure for said electrode means projecting through said channel and side-wall opening into the guide tube, spring means in the chamber urging the contact means closed and urging the switch operating structure radially inwardly of the tubular guide, the operating structure being displaceable radially outwardly with respect to the guide tube for separating the switch contact means, an operating bolt slidable axially in the guide tube and having pro- `file portions selectively registerable with the switch operating structure for causing it tc respectively occupy the positions causing the switch electrode means to be opened or closed, and said insulating body being formed in two parts having contiguous meeting faces extending transversely of the guide tube, and each of said meeting faces containing recess means which pursuant to assembly of said parts ccnjointly constitute the chamber and channel, and means on the guide tube for securing said parts assembled.

3. The combination set forth in claim 2, whereu in there is a mounting stem. comprising said guide sleeve, and said mounting stem having a portion projecting endwise from the insulating body.

4. The combination set forth in claim 2, wherein said insulating body comprises openings leading from the chamber exteriorly of the insulating body and intersected by a plane common thereto and to said channel and extending transn versely of said guide tube, switch terminal members respectively disposed in said openings, the meeting faces of the two parts of said insulating body being coincident with said plane when the parts are assembled, and said meeting faces also containing recess means which pursuant to assembly of the parts form said terminal-memberreceiving openings.

REINHARD P. H. HINDS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,664,876 Douglas Apr. 3, 1928 1,826,105 Veale Oct. 6, 193i 

